Magnetism is a property of materials that are magnetized in a magnetic field, and is classified into paramagnetism, diamagnetism, ferromagnetism, superparamagnetism, etc. according to characteristics. When a magnetic field is applied to the outside of a material, magnetic moments of atoms are aligned by the magnetic field, and a characteristic of the magnetism is classified according to the alignment characteristic of the magnetic moments. In general, the magnetic property of a material is unique, and two or more magnetic materials are frequently combined into an alloy to adjust the magnetic property.
A method of producing various magnetic nanoparticles is disclosed in a recent paper “Chemical synthesis of magnetic nanoparticles” Taeghwan Hyeon, CHEM. COMMUN., 2003, 927-934. This paper discloses a method of producing various magnetic nanoparticles such as oxidized steel nanoparticles in the colloidal state, iron-platinum compound nanoparticles, and iron-cobalt compound nanoparticles.
Methods of adjusting a magnetic property using magnetic nanoparticles are attracting attention as technology that can be widely used in the field of information storage devices and sensors.